Dairy products, such as cheese, butter and curd are among the most frequently consumed foodstuffs. They are most nourishing due to their high protein and the presence of substances and vitamins essential for good nourishment. However, these dairy products when prepared by conventional methods can be stored only for a relatively short time and their storage and transportation are relatively expensive due to their high water content. Thus it is highly desirable to produce dairy products with a diminished water content, particularly for large-scale uses as mass feeding, and public catering.
A basic requirement is that these preserved products should resemble the traditionally prepared dairy products with respect to taste, composition, nutritive value and organoleptic characteristics.
Known processes for preserving cheese, are aimed at concentrating the protein and fat content and at decreasing the water content of cheese. Traditional drying processes are described e.g. in U.S. Pat. Nos. 3,482,999; 2,401,320; and 1,752,821, however, the methods described in those patents require the use of a high drying temperature causing the removal and alteration of the desired volatile, content, odor, taste and aromatizing substances thus, they do not ensure that the finished product maintains the organoleptic properties which are characteristic of the starting fresh cheese.
According to a process described in U.S. Pat. No. 3,694,231 an easy-flowing, granular, dehydrated cheese product can be prepared by chopping the cheese pieces and freeze drying them by freezing in a liquified gas (e.g. nitrogen) and then drying the resulting cheese granules at 20.degree. C. in a frozen state in a fluidized bed. This is expensive and, therefore, uneconomical.
In U.S. Pat. Nos. 3,573,931 and 3,573,930 the cheese with a high water content is extruded in an extruding press and then dried at a high temperature to a lowered water content of 17%.
United Kingdom patent specification No. 2,073,574 describes the preparation of preserved cheese products by adding powdered .alpha.-cellulose to the cheese to be processed, then chopping and drying it to a maximum water content of 18% by mass, preferably of 7 to 10% by mass. According to the examples of that patent, drying is carried out at a temperature of 100.degree. to 400.degree. F. (38.degree. to 204.degree. C.), while preventing the cheese from melting while drying. This process avoids melting, but the aromatizing substances of the cheeses are damaged by the high temperature drying and the additive binds only the water content and is otherwise unsuitable for binding the fat content. No data are given concerning the shelf life of the cheese obtained.